Modular fixed-level work platform

ABSTRACT

A plurality of identical platform and ladder modules can be releasably connected together in various combinations to achieve a unitary rigid structure that establishes a fixed level work platform of the desired configuration supported by steps providing access thereto. The construction of the modules permits them to be manufactured at one location, and individually shipped to a remote location where they can be assembled in-situ into the desired configuration.

[ 51 Oct. 17,1972

United States Patent Dohan [54] MODULAR FIXED-LEVEL WORK 3,529,695Rowley...................... 3,092,383 6/1963Dunn.........................182/1 15 PLATFORM [72] Inventor:

William L. Dohan, Downingtown, Pa.

Primary Examiner-Reinaldo P. Machado Attorney-Paul & Paul ABSTRACT Aplurality of identical platform and ladder modules I73] Assignee:Ballymore Company, West Chester,

22 Filed: Oct. 6, 1970 21 Appl. No.: 78,441

can be releasably connected together in various combinations to achievea unitary rigid structure that establishes a fixed level work platformof the desired configuration supported by steps providing accessthereto. The construction of the modules permits them to be manufacturedat one location, and in- [58] Field ofSearch......182/l15,113,179,178,119,

182/118 situ into the desired configura- [56] References Cited 9 Claims,4 Drawing Figures UNITED STATES PATENTS 3/1967Gnehm...........;..........182/1l5 PATENTEUUBI 11 m2 3598,51 1

Fig 4 INVENTOR.

William l Dohon ATTOR NEYS PATENIEDnm 17 I972 SHEEI 2 BF 2 INVENTORWilliam L. Dohon ATTORNEYS.,

MODULAR FIXED-LEVEL WORK PLATFORM BRIEF SUMMARY OF THE INVENTION Thisinvention relates to fixed-level work platforms that can be constructedin-situ from a plurality of identical modules.

The conventional practice for providing manual access to existingmachinery, equipment or physical structures, involves thecustom-construction of a unitary structure peculiar to the size, shapeand capacity of the particular project. When such construction iscarried out at the site, the steps, platforms, supports, guardrails,etc. must be designed, laid out, fabricated and built at the site, aprocedure usually inconvenient and likely to be more expensive thanengaging a specialist to do this work in his shop. The latter approach,however, requires shipment of the completed platform to the site, acostly procedure in view of the usually large volume-to-weight ratio. Ineither case, the configuration of the structure so constructed is fixed,with the result that modification or re-use of the structure at adifferent location is not easily accomplished. It is the primary objectof the present invention, therefore, to provide a fixed-level workplatform which can be manufactured relatively inexpensively at alocation remote from the site where it can be easily erected and, ifnecessary, modified as required.

Briefly, the invention involves providing a plurality of identicalplatform modules and ladder modules that can be releasably connectedtogether in various combinations to achieve a unitary rigid structurethat establishes a fixed-level work platform supported by steps or rungladder sections that provide access thereto. By reason of the identicalnature of the modules, they can be fabricated easily in large quantitiesat a central location; and pre-selected numbers can be relativelyinexpensively shipped to a remote location where the modules can beassembled in a predetermined manner to establish the desiredconfiguration. Furthermore, should the requirements of the user change,the original configurations can be modified easily, or even disassembledand transported easily to a new location.

The more important features of this invention have thus been outlinedrather broadly in order that the detailed description thereof thatfollows may be better understood, and in order that the contribution tothe art may be better appreciated. There are, of course, additionalfeatures of the invention that will be described hereinafter and whichwill also form the subject of the claims appended hereto. Those skilledin the art will appreciate that the conception upon which thisdisclosure is based may readily be utilized as a basis for designingother structures for carrying out the several purposes of thisinvention. It is important, therefore, that the claims to be grantedherein shall be of sufficient breadth to prevent the appropriation ofthis invention by those skilled in the art.

BRIEF DESCRIPTION OF VIEWS OF THE DRAWING FIG. 1 is a schematicside-view of a fixed-level work platform built in accordance with thepresent invention.

FIG. 2 is an exploded perspective view of a portion of another fonn offixed-level work platform;

FIG. 3 is a schematic side view of still another form of fixed-levelwork platform.

FIG.'4 is a sectional view taken along the lines 4-4 of FIG. 2.

DETAILED DESCRIPTION Referring now to FIG. 1, reference numeral 10designates a typical fixed level work platform constructed in accordancewith the present invention. Platform 10 is relatively simple andillustrates an assembly of two platform modules 11 and four laddermodules 12. Using different combinations of these modules, variousplatforms can be constructed to go around, over or under the mostcomplicated shapes and establish single or multiple work surfacesaccessible by steps.

As seen in FIG. 2,,each platform module 11 comprises a pair of separateoverlying identical rectangular frames 13 each of which has a pair ofidentical parallel horizontal members 14 attached to the free ends 15 ofa pair of identical parallel vertical members 16. Members l4 and 16 aremetal tubes and the attachment therebetween is by way of welding. Theupper one 17 of the horizontal members 14 of each pair of frames 13constitutes a handrail.

Intermediate the ends of vertical members 16 is located a platformdefined by tread means 18 which may include a rectangular reinforcedmetal frame covered with a metal mesh and welded at each corner to oneof the vertical members 16 which each contain a pair of spaced holes 19.The axis of each hole 19 is normal to the axis of the vertical membersand aligned with the plane of the frames.

' One of the simplest work platform would include two platform modules11 connected together to establish a platform double the area of treadmeans 18. To achieve such a platform, the right-hand vertical members 20of a pair of platform frames 13 of module A are abutted with theleft-hand vertical members 21 of a pair of platform frames 13 of anadjacent module B whereby the handrails 17 of the modules are aligned,and holes 19 are aligned as shown in FIG. 2. Bolts 22 passing throughaligned holes 19 are provided with nuts (not shown) by which module A isrigidly attached to module B. Vertical members 20, 21 abut throughouttheir entire length so that when modules A and B are bolted together astrong unitary work platform is established. One form of support for andaccess to this platform is provided by ladder modules 12 shown best inFIG. 1.

Referring again to FIG. 2, ladder modules 12 comprise a pair of separateoverlying identical parallelogram frames 23 each of which has a pair ofidentical parallel inclined members 24 attached to the free ends 25 of apair of identical parallel vertical members 26. Members 24 and 26 aremetal tubes and the attachment therebetween is by way of welding. Theupper one of the inclined members of each pair of frames 23 constitutesa handrail, and the other member constitutes a step support to which aplurality of spaced step means 27 are attached. Each step means 27comprises a rectangular frame on the surface of which is welded a metalmesh to provide a non-slip tread surface. Two corners of the frame ofeach step means are welded to member 24 with the metal mesh defining aplane perpendicular to the axes of vertical members 26 each of whichcontains a pair of spaced holes 28. The axis of each hole 28 is normalto the axis of vertical member 26 and is aligned with the plane of theframe. As shown in FIG. 2, a reinforcing bar 29 is welded to members 26of each frame 23 and serves to support the projecting edge of each ofthe step means 27. The tread means 18 of each platform module 11 isvertically spaced from the lower horizontal member 14 of the platformframes by a distance equal to the vertical spacing between the planesdefined by step means 27 of the ladder modules. The width of the stepmeans 27 is such that the spacing between frames 23 of a ladder moduleis the same as the spacing between the frames 13 of a platform module.It should be understood that the number of step means shown anddescribed is meant to be illustrative of the invention, and fewer ormore step means can be provided.

. In the event the particular use to which the work platform is to beput requires elevation of the platform to a height of twice one of theladder modules, two of the latter modules can be connected together in amanner similar to which two platform modules are connected together.Accordingly, opposite vertical members 30 at the upper end of a pair ofladder frames 23 of one module C are abutted with opposite verticalmembers 31 at the lower end of the frames of another module D wherebythe handrails of the modules (e.g., upper members 24 of each frame 13)are aligned, and holes 28 are aligned as shown in FIG. 2. Bolts 22passing through aligned holes 28 are provided with nuts (not shown) bywhich module C is rigidly attached to module D. Vertical members 30, 31abut throughout their entire length so that when modules C and D-arebolted together a strong unitary ladder structure is established.

In order to construct the work platform illustrated in FIG. 1, twoplatform modules 11 would be bolted together as described above; and, toeach of these modules would be bolted a pair of ladder modules that hadbeen previously bolted together as described. In such case, the oppositevertical members 30 at the upper end of a pair of ladder frames 23 ofladder module D, for example, are abutted with, for example, right-handvertical members of platform module B whereby handrails 17 of the latterare contiguous to the upper inclined members 24 of the ladder module.Vertical members 26 of the ladder modules are the same length asvertical members 16 of the platform modules so that the holes 28 inmembers 26 are aligned with holes 19 in members 20. Bolts 22 can then bepassed through the aligned holes to rigidly attach the ladder modules tothe platform modules. Similarly, a pair of ladder modules can beattached to left-hand vertical members 21 of module A. In this way, theinline configuration shown in FIG. 1 can be constructed.

As shown in the drawing, all of the platform modules are identical, andall of the ladder modules are identical. All of the vertical members onthe ladder module have mitred ends and are of the same length; and allof the vertical members of the platform modules have square ends and areof the same length. In each ladder module, the upper and lower inclinedmembers are the same length; and in each platform module, the horizontalmembers are the same length. Thus, members of only four differentlengths are required for these modules. Preferably, the members aretubular and are welded together permitting conventional metal workingequipment to be used to effect considerable time and material savings infabrication of these two basic modules. Furthermore, the ladder andplatform modules can be used in various work platforms. FIG. 3 isillustrative of one such variety. Many other configurations are ofcourse possible.

In addition to being conducive to rapid and inexpensive fabrication, thedisclosed modular concept permits a user at a location remote from theplace at which fabrication of the modules occurs, to design his own workplatform to meet his own particular requirements, and to order thenecessary modules from the module fabricator. Shipment of the modules,unassembled, is relatively inexpensive because the modules can be nestedto increase the volume-to-weight ratio as compared to the shipment of afully assembled configuration. Erection of the work platform is easilyachieved with minimum effort by reason of the design of the modules andthe expedient of using standard nuts and bolts to clamp the modulestogether and establish a rigid unitary structure.

The truss nature of the modules provides a sturdy structure, but it issometimes necessary to provide extra support for the platform,particularly when many platform modules are interconnected. When this isnecessary, an auxiliary support like that designated by referencenumeral 40 can be used. Support 40 includes a pair of identical verticallegs 41 which preferably are tubular and of rectangular cross-section,and a plurality of rungs 42 in the form of tubes welded to the insidesurfaces 43 of legs 41. Rungs are spaced apart a'convenient distance sothat, if necessary or desired, support 40 can serve as a ladder.Adjacent the free end of each vertical leg 41, and on the surface 43, iswelded auxiliary vertical member 44 which is identical to members 16 ofthe previously described platform module. Each of members 44 have a pairof holes 45 spaced apart the same distance holes 19 and holes 28 arespaced part in the vertical members of the ladder and platform modules.Consequently support 40 can be interposed between a pair of platformmodules as indicated at 46 in FIG. 3 or between a platform module and aladder module as indicated at 47 in FIG. 3. It should also be noted thata step ladder can be constructed when ladder modules are attached on oneor both sides of an auxiliary support. Note that the length of support40 is modular in that the length is dependent upon the platform level atwhich the support is to function. Thus, support 46 to support the secondlevel of platform as shown in FIG. 3 has longer legs than support 47which supports only the first level.

In order to achieve a rigid connection between the auxiliary support andadjacent platform modules, righthand vertical members 20 of module B,for example, are abutted with one side 48 of member 44 on support 40,and left-hand vertical members 21 of an adjacent platform module (notshown) are abutted with the opposite side 49 of member 44 (see FIG. 4).Holes 19 in vertical members 20 and 21 are aligned with holes 45 andbolts (not shown) can be inserted to permit a rigid connection betweenthe modules to be achieved. The handrails 17 of the adjacent platformmodules are then in alignment.

Sometimes a user requirement calls for a work platform with aright-angle approach, e.g., a platform in which one or the other laddermodules are to be directed at right angles to the axis of the workplatform. In such case, a special right angle module like thatdesignated by reference number 50 can be used. Module 50 has a rearrectangular frame 51 and a front frame 52. Frame 51 has a pair ofidentical parallel horizontal members 53 attached to the free ends 54 ofa pair of identical parallel vertical members 55. The upper one ofmembers 53 constitutes a handrail.

Frame 52 has a single lower horizontal member 56 and a pair of spacedvertical support units 57 attached to member 56 near opposite ends. Eachsupport unit 57 is U-shaped and includes a pair of vertical supportmembers 58 interconnected by a horizontal tiemember 59. The free ends ofmembers 58 are welded to member 56 to define a left-hand and aright-hand support unit. The spacing between the inner one of members 58of left-hand support unit 57 and the inner one of members 58 of theright-hand support unit 57 is the same .as the spacing between theframes 23 of a ladder module, which is also the same as the spacingbetween the'frames 13 of a platform module.

Platform 63 in the form of a reinforced frame covered with metal mesh iswelded to vertical members 55, 58 so that the plane of the platform isnormal to the plane of frames 51 and 52. Platform 63 is spaced fromlower horizontal members of frames 51 and 52 a distance equal to thespacing between tread means 18 and lower members 14 of the platformmodules. In addition, the spacing between frames 51 and 52 of module 50is the same as the spacing between frames 13 of platform module 11 andeach outer member of module 50 are provided with spaced holes 64 whichmatch spaced holes 19 in vertical members 16 of the platform modules,and spaced holes 28 in vertical member 26 of the ladder modules. Whilethe drawing shows a platform module rigidly attached to right-handvertical members 55, 58 (which are the same length as members 16 bymeans of bolts 22, it is also possible to attach either a ladder moduleor an auxiliary support to members 55, 58 by reason of the spacingtherebetween. Similarly, a ladder module or a platform module or anauxiliary support can be attached to the left-hand vertical member.

The two inner members 58 of support units 57 are each provided withspaced holes 65 which match spaced holes 19 in vertical members 16 ofthe platform modules, and spaced holes 28 in vertical members 26 of theladder modules. While the drawing shows a ladder module rigidly attachedto inner members 58 (which are the same length as members 16) by meansof bolts 22, it is also possible to attach a platform module to innermembers 58.

When additional support for module 50 is to be provided by auxiliarysupport 40, members 44 can be placed abutting right-hand verticalmembers 55, 58 at the right of the module, or abutting left-handvertical members 55, 58 at the left of the module, depending on theconfiguration of the platform desired. Sometimes, support 40 is used toterminate a module 50 or a platform module 11 at either the left orright hand side thereof. In such case, a tubular member like rung 42would be mounted on top of members 44 by welding to pins 66 insertedinto the top of members 44 in situ to form an end hand rail.

The flexibility of the above described fixed-level work platform isenhanced by providing a caster module designated by reference numeral70.-Module 70 includes a channel shaped base member 71 at each end ofwhich are mounted swiveling casters 72. In the web of base member 71 areholes 73 which can be aligned with lower holes 28 in lower verticalmembers 26 of frames 23 of the ladder modules. Bolts 22 can then be usedto rigidly attach module 70 to the ladder module. Suitable holes 74 inclips 75 welded to the inside lower ends of vertical legs 41 ofauxiliary support 40 are also provided to accommodate the attachment tosuch support of another module 70.

What is claimed is:

l. A fixed level work platform that can be constructed in-situcomprising a plurality of identical platform modules releasablyconnected together for defining a fixed-level work platform, and laddermeans releasably connected to a platform module at each end of said workplatform for providing steps leading to and support for said work.platform, and wherein the ladder means at one end of said work platformis constituted by a pair of ladder modules, each ladder modulecomprising a pair of separate overlying identical parallelogram ladderframes each of which has a pair of identical parallel inclined membersattached to the free ends of a pair of identical parallel, verticalmembers; the upper one of the inclined members of each pair of ladderframes constituting a step support, and a plurality of spaced step meansattached to said other members constituting steps, there being in eachvertical member a pair of spaced holes, opposite vertical members of apair of ladder frames of one module being abutted with opposite verticalmembers of a pair of ladder frames of an adjacent module whereby thehandrails are aligned and the holes in the last mentioned verticalmembers are aligned, and bolt means passing through the aligned holesfor rigidly attaching said one module to said adjacent module.

2. A fixed level work platform that can be constructed in-situcomprising a plurality of identical platform modules releasablyconnected together for defining a fixed-level work platform, and laddermeans releasably connected to a platform module at each end of said workplatform for providing steps leading to and support for said workplatform, and wherein each platform module comprises a pair of separateoverlying identical rectangular platform frames each of which has a pairof identical parallel, horizontal members attached to the free ends of apair of identical parallel vertical members, the upper one of thehorizontal members of each pair of platform frames constituting ahandrail, and tread means attached to each of the vertical membersconstituting a platform, there being a pair of spaced holes in eachvertical member, opposite vertical members of a pair of platform framesof one module being in abutment with opposite vertical members of a pairof platform frames of an adjacent module whereby the handrails arealigned and the holes in the last mentioned vertical members arealigned, and bolt means passing through the aligned holes for rigidlyattaching said one module to said adjacent module.

3. A work platform according to claim 2 wherein said ladder means at oneend of said work platform includes a right-angle module comprising arear rectangular frame having a pair of identical parallel horizontalmembers attached to the free ends of a pair of identical parallelvertical members, the upper horizontal member of said rear frameconstituting a handrail, a front frame having a single lower horizontalmember and a pair of spaced vertical support units attached to the freeends of the last mentioned horizontal member,

and tread means attached to the vertical members of said rear frame andsaid support units, there being a pair of spaced holes in the verticalmember of said rear frame at the other end thereof and in the othersupport unit, the last mentioned vertical member and support unit beingspaced apart a distance equal to the distance between said pair ofplatform frames and being in abutment with opposite vertical members ofa pair of platform frames of a platform module at one end of said workplatform whereby the handrail of said right-angle module is aligned withone of the handrails of the last mentioned platform module and the holesin the vertical member and support unit of the right-angle module arealigned with the holes in vertical members of said last mentionedplatform module, and bolt means passing through the aligned holes forrigidly attaching the right angle module to said last mentioned platformmodule.

4. A work platform according to claim 2 wherein the ladder means at eachend of said work platform is constituted by a ladder module each ofwhich comprises a pair of separate overlying identical parallelogramladder frames each of which has a pair of identical parallel, inclinedmembers attached to the free ends of a pair of identical parallel,vertical members, one of the inclined members of each pair of ladderframes constituting a handrail, and the other of the incline membersconstituting a step support, and a plurality of spaced step meansattached to said other members constituting steps, there being in eachvertical member a pair of spaced holes, the spacing between the ladderframes being the same as the spacing between the platform frames,opposite vertical members of a pair of ladder frames the respectiveladder modules being in abutment with opposite vertical members of apair of platform frames of the respective platform modules at each endof the work platform whereby the handrails of said ladder modules arecontiguous to the handrails of said one platform module and the holes inthe last mentioned vertical members are aligned, and bolt means passingthrough the aligned holes for rigidly attaching together the abuttedmodules.

5. A work platform according to claim 4 wherein each of said members istubular.

6. A work platform according to claim 5 wherein there is a step means oneach ladder module attached to the ladder frames thereof at the uppercorners of the overlying parallelograms.

7. A fixed level work platform that can be constructed in-situcomprising a pluralit form modules releasably connected f ogether fordefining a fixed-level work platform, and ladder means releasablyconnected to a platform module at each end of said work platform forproviding steps leading to and support for said work platform, andwherein each platform module comprises a pair of separate overlyingidentical rectangular platform frames each of which has a pair ofidentical parallel, horizontal members attached to the free ends of apair of identical parallel and vertical members, one of the horizontalmembers of each pair of platform frames constituting a handrail, andtread means attached to each of the vertical members constituting aplatform, there being a pair of spaced holes in each vertical member,and an auxiliary support for supporting said work platform, said supporthaving a pair of vertical legs to the inside of each of which is rigidlyattached a vertical member having a pair of spaced holes, oppositevertical members of a pair of platform frames of one module being inabutment with one side of the vertical members on the legs, and theopposite vertical members of a pair of platform frames of an adjacentmodule being in abutment with the opposite side of the vertical memberson the legs whereby the handrails are aligned and the holes in the lastmentioned vertical members are aligned, and bolt means passing throughthe aligned holes for rigidly attaching the platform modules to saidauxiliary support.

8. A work platform according to claim 7 wherein caster wheels arereleasably attached to the free ends of said auxiliary support.

9. A work platform according to claim 8 wherein said ladder means at oneend of said work platform also includes a ladder module which comprisesa pair of separate overlying identical parallelogram frames each ofwhich has a pair of identical parallel inclined members attached to thefree ends of a pair of identical parallel vertical members, the upperone of the inclined members of each pair of frames constituting ahandrail, and the other of the inclined members constituting a stepsupport, and a plurality of spaced step means attached to said othermembers constituting steps, there being a pair of spaced holes in thevertical members of said frame and in said support units, the lastmentioned vertical members and support units being spaced apart the samedistance and being in abutment whereby the spaced holes are aligned, andbolt means passing through the aligned holes for rigidly attaching theright angle module to said ladder module.

of identical plat-

1. A fixed level work platform that can be constructed in-situcomprising a plurality of identical platform modules releasablyconnected together for defining a fixed-level work platform, and laddermeans releasably connected to a platform module at each end of said workplatform for providing steps leading to and support for said workplatform, and wherein the ladder means at one end of said work platformis constituted by a pair of ladder modules, each ladder modulecomprising a pair of separate overlying identical parallelogram ladderframes each of which has a pair of identical parallel inclined membersattached to the free ends of a pair of identical parallel, verticalmembers; the upper one of the inclined members of each pair of ladderframes constituting a step support, and a plurality of spaced step meansattached to said other members constituting steps, there being in eachvertical member a pair of spaced holes, opposite vertical members of apair of ladder frames of one module being abutted with opposite verticalmembers of a pair of ladder frames of an adjacent module whereby thehandrails are aligned and the holes in the last mentioned verticalmembers are aligned, and bolt means passing through the aligned holesfor rigidly attaching said one module to said adjacent module.
 2. Afixed level work platform that can be constructed in-situ comprising aplurality of identical platform modules releasably connected togetherfor defining a fixed-level work platform, and ladder means releasablyconnected to a platform module at each end of said work platform forproviding steps leading to and support for said worK platform, andwherein each platform module comprises a pair of separate overlyingidentical rectangular platform frames each of which has a pair ofidentical parallel, horizontal members attached to the free ends of apair of identical parallel vertical members, the upper one of thehorizontal members of each pair of platform frames constituting ahandrail, and tread means attached to each of the vertical membersconstituting a platform, there being a pair of spaced holes in eachvertical member, opposite vertical members of a pair of platform framesof one module being in abutment with opposite vertical members of a pairof platform frames of an adjacent module whereby the handrails arealigned and the holes in the last mentioned vertical members arealigned, and bolt means passing through the aligned holes for rigidlyattaching said one module to said adjacent module.
 3. A work platformaccording to claim 2 wherein said ladder means at one end of said workplatform includes a right-angle module comprising a rear rectangularframe having a pair of identical parallel horizontal members attached tothe free ends of a pair of identical parallel vertical members, theupper horizontal member of said rear frame constituting a handrail, afront frame having a single lower horizontal member and a pair of spacedvertical support units attached to the free ends of the last mentionedhorizontal member, and tread means attached to the vertical members ofsaid rear frame and said support units, there being a pair of spacedholes in the vertical member of said rear frame at the other end thereofand in the other support unit, the last mentioned vertical member andsupport unit being spaced apart a distance equal to the distance betweensaid pair of platform frames and being in abutment with oppositevertical members of a pair of platform frames of a platform module atone end of said work platform whereby the handrail of said right-anglemodule is aligned with one of the handrails of the last mentionedplatform module and the holes in the vertical member and support unit ofthe right-angle module are aligned with the holes in vertical members ofsaid last mentioned platform module, and bolt means passing through thealigned holes for rigidly attaching the right angle module to said lastmentioned platform module.
 4. A work platform according to claim 2wherein the ladder means at each end of said work platform isconstituted by a ladder module each of which comprises a pair ofseparate overlying identical parallelogram ladder frames each of whichhas a pair of identical parallel, inclined members attached to the freeends of a pair of identical parallel, vertical members, one of theinclined members of each pair of ladder frames constituting a handrail,and the other of the incline members constituting a step support, and aplurality of spaced step means attached to said other membersconstituting steps, there being in each vertical member a pair of spacedholes, the spacing between the ladder frames being the same as thespacing between the platform frames, opposite vertical members of a pairof ladder frames the respective ladder modules being in abutment withopposite vertical members of a pair of platform frames of the respectiveplatform modules at each end of the work platform whereby the handrailsof said ladder modules are contiguous to the handrails of said oneplatform module and the holes in the last mentioned vertical members arealigned, and bolt means passing through the aligned holes for rigidlyattaching together the abutted modules.
 5. A work platform according toclaim 4 wherein each of said members is tubular.
 6. A work platformaccording to claim 5 wherein there is a step means on each ladder moduleattached to the ladder frames thereof at the upper corners of theoverlying parallelograms.
 7. A fixed level work platform that can beconstructed in-situ comprising a plurality of identical platform modulesreleasably connected together for defining a fixEd-level work platform,and ladder means releasably connected to a platform module at each endof said work platform for providing steps leading to and support forsaid work platform, and wherein each platform module comprises a pair ofseparate overlying identical rectangular platform frames each of whichhas a pair of identical parallel, horizontal members attached to thefree ends of a pair of identical parallel and vertical members, one ofthe horizontal members of each pair of platform frames constituting ahandrail, and tread means attached to each of the vertical membersconstituting a platform, there being a pair of spaced holes in eachvertical member, and an auxiliary support for supporting said workplatform, said support having a pair of vertical legs to the inside ofeach of which is rigidly attached a vertical member having a pair ofspaced holes, opposite vertical members of a pair of platform frames ofone module being in abutment with one side of the vertical members onthe legs, and the opposite vertical members of a pair of platform framesof an adjacent module being in abutment with the opposite side of thevertical members on the legs whereby the handrails are aligned and theholes in the last mentioned vertical members are aligned, and bolt meanspassing through the aligned holes for rigidly attaching the platformmodules to said auxiliary support.
 8. A work platform according to claim7 wherein caster wheels are releasably attached to the free ends of saidauxiliary support.
 9. A work platform according to claim 8 wherein saidladder means at one end of said work platform also includes a laddermodule which comprises a pair of separate overlying identicalparallelogram frames each of which has a pair of identical parallelinclined members attached to the free ends of a pair of identicalparallel vertical members, the upper one of the inclined members of eachpair of frames constituting a handrail, and the other of the inclinedmembers constituting a step support, and a plurality of spaced stepmeans attached to said other members constituting steps, there being apair of spaced holes in the vertical members of said frame and in saidsupport units, the last mentioned vertical members and support unitsbeing spaced apart the same distance and being in abutment whereby thespaced holes are aligned, and bolt means passing through the alignedholes for rigidly attaching the right angle module to said laddermodule.